1. Field of the Invention
The present invention relates to a heat exchanger for the heat exchange between a hot gas and a flowing medium that is conveyed in tube bundle heat transfer surfaces, especially a steam generator for gas-cooled high-temperature reactors. Included is a pressure tank, a heat exchanger vessel in which are disposed the tube bundles, a hot gas conduit that is connected to a gas inlet on one end of the wall of the heat exchanger. Also included are a gas guiding tube, a gas outlet from the heat exchanger vessel to a circulation fan, and feed and withdrawal lines for the flowing medium that is to be heated up. As the hot gas flows into the heat exchanger, it is essentially deflected by 90.degree..
2. Description of the Prior Art
A heat exchanger of this general type is known from Dubbel "Taschenbuch fuden Maschinenbau", 15th edition (1983), Pages 588 and 601, 602.
In copending patent application Ser. No. 868,242 Pallark filed May 28, 1986, and belonging to the Assignee of the present application, a heat exchanger includes a gas guiding tube for the hot gas conduit opened into the wall of the heat exchanger from the side. An annular channel is disposed after the gas inlet in the heat exchanger wall, with this annular channel being delimited inwardly by a riser that forms the gas outlet to the circulation fan and is disposed concentric to the walls of the pressure tank and the heat exchanger. In this heat exchanger, the gas enters the tube bundles from the annular chamber and exits the tube bundle accompanied by a deflection of essentially 180.degree. , whereupon the gas is supplied to the circulation fan via the riser. With this arrangement, the gas in the annular chamber flows between the heat exchanger, especially a steam generator wall, and the wall of the pressure tank in the direction toward the 90.degree. deflection, and is previously introduced into the riser through a plurality of gas channels that extend through the upper end of the steam generator wall; the gas is fed from there to the circulation fan, with the riser being disposed in that portion of the hot gas deflection mechanism that extends parallel to the axis of the tank and effects the 90.degree. deflection.
With the initially described arrangement, as well as with the arrangement disclosed in the aforementioned copending U.S. patent application, the heat transfer surfaces of the steam generator are disposed about a dead space.
An object of the present invention is to design a heat exchanger of the type described in the aforementioned patent application in such a way that the gas that leaves the tube heat transfer surfaces is supplied to the circulation pump in as simple a manner as possible, and in particular that gas channels are avoided that would have to extend through the wall of the steam generator as well as through the compensation tube bundles associated with the upper end of the steam generator wall.